One of my BR and one of my SG died today within four hours of one another. The BR was lethargic this morning at about 8am and by noon had expired. I went out to assemble my 30 minute OverEZ large coop (which took three and a half hours) and when checked my chicks and one of my SGs was dead. I am confused! There are four others in the brooder. Should I take any precautions to protect the others?